The present invention relates to a gas sensor chamber and an odor detection method that uses the chamber according to the invention.
One non-limiting example of an application of the chamber according to the invention is in apparatus for detecting aromas or odors produced by food products. This specification expressly refers to uses of this kind but without thereby restricting the scope of the invention.
Apparatus for detecting the aromas or odors produced by food products is used to check the quality of a food product not only in terms of the constancy of its properties during the preparation process but also to detect aging or spoiling.
This type of check is very useful because it provides information quickly without having to come into contact with the product to be checked.
Devices are known which detect aromas or odors using artificial sensors that work in a manner similar to the olfactory system of mammals.
Chemical resistors are one example of sensors of this kind. This type of sensor is made from special materials that absorb the gas/vapor to be detected and produce a change in electrical resistance.
The substance absorbed by the sensor material produces a change in the resistance to the passage of current through an electrical circuit to which the sensor is connected.
Usually, the sensors used for olfactory measurement analysis are transducers which convert an interaction with defined gaseous substances into electrical signals.
Each sensor is differently sensitive to a specific group of gaseous substances and therefore, to produce an “odor print”, that is to say, a specific aroma or odor, with satisfactory precision, several olfactory sensors are required, each differently sensitive to that specific group of gaseous substances.
Further, once the sensors used to identify gas mixtures have generated a certain signal, they must be cleared of the gas they have absorbed before they can proceed to carrying out another analysis.
It follows that the arrangement of the sensors and the shape of the chamber in which the sensors are located are very important factors for the correct identification of the odor or aroma.
One gas sensor arrangement is known from patent U.S. Pat. No. 6,516,653-B2.
That document describes an apparatus device comprising one or more gas or vapor sensors located in a room where concentrations or mixtures of gases or vapors have to be monitored, and with a diffusion body placed in front of the sensors.
According to the invention described in that document, the gas sensors, whose responsiveness is influenced by the design of the container enclosing the space to be monitored, by contamination or by static conditions in the space to be monitored, are positioned in a duct where a flow that accelerates the diffusion of the gases or vapors to be analyzed is generated, thus increasing the responsiveness of the gas sensors.